Paxlovid—Pfizer’s antiviral Covid-19 treatment—is 37% effective at preventing hospitalization or death in high-risk patients compared with no treatment, according to a studypublished Thursday in the JAMA Network Open, well below the 88% effectiveness rate Pfizer and regulators reported in clinical trials in 2021
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The study also found another antiviral Covid-19 treatment, Merck’s Lagevrio, was 42% effective in preventing hospitalization or death and 77% effective against death alone.
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Why the effectiveness has fallen. The study authors noted the clinical trials were conducted among unvaccinated patients who had limited natural immunity, whereas this study was conducted in a real-world population including vaccinated and previously infected patients who had some other defenses against the coronavirus. They also noted the original clinical studies were completed when the Delta variant was the most common strain of the virus while their study was conducted when the Omicron variant was, suggesting that the drug could work differently with different strains.
而且，这药不能减少long Covid
